| Full Name | Digital Negative file format |
| Format ID | ImGearFormats.DNG |
| File Extension(s) | *.dng |
| Data Type | Bitmap (2D raster) |
| Data Encoding | Binary |
| Multi-Page Support | No |
| Alpha Channel Support | No |
| Metadata Update Support | No |
ImageGear Supported Versions
- Version 1.0.0.0
- Version 1.1.0.0 a fixed incompatibility in JPEG Lossless compression, added new tags
ImageGear Supported Features
- IGFilterFormatFlags.DETECTSUPPORT - autodetection
- IGFilterFormatFlags.PAGEREADSUPPORT - single page file reading
ImageGear Read Support
- ImGearCompressions.NONE
- Without color reconstruction: Grayscale - 16 bpp;
- With color reconstruction: RGB - 24, 48 bpp*
- ImGearCompressions.JPEG
- Without color reconstruction: Grayscale - 16 bpp;
- With color reconstruction: RGB - 24, 48 bpp*
* 8bpc DNG loading has been enabled via promoting the image to 16bpc before loading.
ImageGear Write Support
None.
ImageGear Filter Control Parameters
| Filter Control Parameter | Type | Default Value | Available Values | Description |
|---|---|---|---|---|
| ApplyColorSpaceConversion | bool | true | false, true | Set to true to convert raw image to linear sRGB colorspace during loading. Has effect only if ApplyLowLevelProcessing is true. |
| ApplyLowLevelProcessing | bool | true | false, true | If true, ImageGear applies initial processing stages on the Raw image. If false, ImageGear loads Raw image without any post-processing. See also ApplyColorspaceConversion and ApplyToneCorrection parameters. |
| ApplyToneCorrection | bool | true | false, true | Set to true to automatically adjust image tone and apply sRGB gamma correction during loading. Has effect only if both ApplyLowLevelProcessing and ApplyColorspaceConversion are true. |
| UseCameraWhiteBalance | bool | true | false, true | If true, ImageGear uses white balance settings from the file. Otherwise, white balance is calculated using ImageGear's algorithm. |
Comments
This file format was developed by Adobe as a non-proprietary format for unified storage of "raw" images from digital cameras. DNG image stores unprocessed pixel data obtained from camera's sensor, and keeps information about color, contrast and brightness adjustments, sharpening, as well as many other parameters, in its tags. This provides greater possibilities for image correction and enhancement, compared to commonly used formats such as JPEG, EXIF or TIFF.
The fact that the format is non-proprietary allows software vendors to provide support for DNG in their applications, with complete control over the image reconstruction process.
By default, ImageGear automatically reconstructs colors in raw images during loading. You can disable one or more stages in the automatic color reconstruction, and reconstruct the images programmatically by using ImageGear Processing API. Use filter control parameters to disable specific stages of color reconstruction.
DNG extends TIFF/EP format. It adds a set of new tags for parameters that control reconstruction of full color image from the raw data.
References Used
ADOBE SYSTEMS INCORPORATED. Digital Negative (DNG) specification.